Butyl rubber sealing material and preparation method thereof

Abstract

The invention relates to the field of sealing materials, in particular to a butyl rubber sealing material and a preparation method thereof. Comprising the following components in parts by weight: 50-70 parts of butyl rubber, 30-50 parts of a brominated isobutylene-p-methylstyrene copolymer, 30-50 parts of carbon black, 8-12 parts of an alkyl phenolic resin vulcanizing agent, 3-5 parts of zinc oxide, 1-3 parts of stearic acid, 1-3 parts of an anti-aging agent and 5-10 parts of a plasticizer. The butyl rubber provides ideal air tightness and heat aging resistance, bromine atoms are introduced into the brominated isobutylene-p-methylstyrene copolymer, co-vulcanization with the butyl rubber is achieved, it is ensured that a uniform and stable co-crosslinking network can be formed between the two rubber molecules, and the service life of the rubber is prolonged. The alkyl phenolic resin vulcanizing agent can form a C-C bond with high bond energy with two rubber molecules, so that the thermal aging resistance of the butyl rubber sealing material is effectively improved, the compression set is reduced, and the butyl rubber sealing material with excellent performance is prepared.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sealing materials, in particular to a butyl rubber sealing material and a preparation method thereof. BACKGROUND

[0002] Due to the extremely low air permeability of butyl rubber, it is often used to prepare sealing materials. The obtained butyl rubber sealing material can effectively prevent the leakage of gas and liquid, ensure the normal operation of equipment, improve production efficiency and product quality, and is widely used in various fields.

[0003] The preparation methods of common butyl rubber sealing materials mainly include the following: 1. Simply using butyl rubber as the main raw material, adding some conventional additives such as ordinary carbon black and simple vulcanizing agent, etc. to improve its performance; 2. Blending butyl rubber with other rubbers such as natural rubber, etc. to expect to combine the advantages of different rubbers; 3. Chemical modification of butyl rubber, introducing some special functional groups through chemical reaction, thereby changing its chemical properties and physical properties.

[0004] However, the above-mentioned traditional butyl rubber sealing material performs poorly in terms of aging resistance, and is difficult to meet the requirements of some high-sealing industrial scenarios, and is prone to aging, deformation and other problems, which leads to a decline in sealing effect and affects the normal operation of equipment. SUMMARY

[0005] In order to improve the aging resistance of butyl rubber sealing material, the present application provides a butyl rubber sealing material and a preparation method thereof.

[0006] In a first aspect, the present application provides a butyl rubber sealing material, which adopts the following technical solution: A butyl rubber sealing material, comprising the following components by weight: butyl rubber 50-70 parts, brominated isobutylene-p-methylstyrene copolymer 30-50 parts, carbon black 30-50 parts, alkyl phenol formaldehyde resin vulcanizing agent 8-12 parts, zinc oxide 3-5 parts, stearic acid 1-3 parts, antioxidant 1-3 parts, plasticizer 5-10 parts.

[0007] By adopting the technical scheme, the butyl rubber has extremely low gas permeability, can provide a main sealing and aging resistance basis in a formula, the brominated isobutylene-p-methyl styrene copolymer can greatly improve the vulcanization activity and heat resistance of the system due to the presence of bromine groups, and can realize co-vulcanization with the butyl rubber, improve the vulcanization speed of the whole mixed rubber, and ensure that a uniform and stable co-crosslinking network can be formed between the molecules of the two rubbers; the alkyl phenolic resin vulcanizing agent can form high-energy C-C bonds between the butyl rubber and the brominated isobutylene-p-methyl styrene copolymer under the activation of zinc oxide and stearic acid, effectively improve the heat aging resistance of the butyl rubber sealing material, and the compression permanent set is low, and the presence of the antioxidant can further improve the aging resistance of the butyl rubber sealing material.

[0008] The application can improve the heat aging resistance of the butyl rubber sealing material by compounding butyl rubber and brominated isobutylene-p-methyl styrene copolymer, the butyl rubber provides ideal air tightness and heat aging resistance, the addition of the brominated isobutylene-p-methyl styrene copolymer can introduce bromine atoms, realize co-vulcanization with the butyl rubber, improve the vulcanization speed of the mixed rubber, ensure that a uniform and stable co-crosslinking network can be formed between the molecules of the two rubbers, and the addition of the alkyl phenolic resin vulcanizing agent can form high-energy C-C bonds between the molecules of the two rubbers, effectively improve the heat aging resistance of the butyl rubber sealing material, and reduce the compression permanent set, thereby preparing butyl rubber sealing material with excellent performance.

[0009] Preferably, the antioxidant is at least one of antioxidant RD, antioxidant 4020 and microcrystalline wax.

[0010] Preferably, the antioxidant is a mixture of RD and antioxidant 4020.

[0011] By adopting the technical scheme, the dihydroquinoline structure in the antioxidant RD molecule can provide hydrogen atoms, combine with free radicals generated under the action of heat and oxygen in the butyl rubber and the brominated butyl rubber, and generate stable compounds to interrupt the auto-oxidation chain reaction. At the same time, the antioxidant RD can also decompose hydroperoxide into inactive alcohol or ketone, and the ice surface hydroperoxide is further decomposed to generate new free radicals, thereby inhibiting the initiation of the chain reaction from the source.

[0012] The molecule of antioxidant 4020 contains an aromatic amine group, which has strong reducing property and can terminate the oxidative aging chain reaction by capturing free radicals. Meanwhile, antioxidant 4020 can react with hydroperoxide by hydrogen transfer to decompose it into harmless alcohol and water, thus blocking the secondary aging inducement. In addition, a small amount of double bond exists in rubber, and ozone will preferentially attack the double bond during the use of butyl rubber sealing material, thus causing the molecular chain to break. Antioxidant 4020 can migrate to the surface of rubber to form a dense "amine protective film", which physically blocks the contact between ozone and double bond. The ozone that is not blocked will react with the aromatic amine group of antioxidant 4020, thus protecting the rubber molecular chain.

[0013] Microcrystalline wax can reduce the contact between aging factors and the interior of rubber by physical blocking effect. During the use of butyl rubber sealing material, microcrystalline wax will slowly migrate to the surface of rubber to form a continuous and dense film. This physical film can isolate aging media such as oxygen and ozone, thus reducing the penetration of aging reaction caused by the aging media into the interior of rubber. Meanwhile, it can also reduce the volatilization loss of small molecular components in the rubber compound.

[0014] The antioxidant RD and antioxidant 4020 are compounded into an antioxidant. The polymer structure of antioxidant RD can "anchor" the molecules of antioxidant 4020, thus reducing the volatilization or extraction of antioxidant 4020 at high temperature, effectively prolonging the action time of antioxidant 4020. The quinone imine derivative generated after antioxidant 4020 terminates the free radical can react with the amine intermediate generated by the decomposition of antioxidant RD to form a more stable protective molecule, thus further strengthening the free radical capture efficiency.

[0015] Preferably, the mixing mass ratio of antioxidant RD to antioxidant 4020 is 1-3:1.

[0016] By using the above technical solution, when the proportion of antioxidant RD is too high, the insufficient addition amount of antioxidant 4020 leads to insufficient thickness and poor density of the surface "amine protective film", and ozone easily penetrates the film layer to attack the double bond of rubber, thus causing the molecular chain to break. The ozone that is not blocked lacks chemical capture of antioxidant 4020, directly damages the structure of rubber, further aggravates aging cracking, and reduces the flex fatigue resistance of butyl rubber sealing material.

[0017] When the proportion of antioxidant RD is too low, it cannot effectively interrupt the free radical chain reaction and decompose hydroperoxide, thus causing the heat and oxygen aging to be out of control, and the mechanical properties of butyl rubber sealing material to decrease. Meanwhile, the destruction of crosslinking network will cause the compression permanent deformation of butyl rubber sealing material to increase, thus causing the sealing performance to fail.

[0018] Preferably, modified ceramic microspheres are further added, and the addition amount of the modified ceramic microspheres is 5-15 parts.

[0019] Through the above technical solution, the modified ceramic microspheres are hollow microspheres, which play the role of "ball bearing" in the rubber compound, effectively reduce the viscosity of the polymer melt, improve the mixing and extrusion process, and reduce the processing defects. Moreover, the modified ceramic microspheres have a certain compressibility, which can adjust the hardness and compression permanent deformation performance of the rubber compound to adapt to different sealing application scenarios.

[0020] The modified ceramic microspheres have ideal compatibility with butyl rubber and brominated isobutylene-p-methylstyrene copolymer, so that the modified ceramic microspheres can be uniformly dispersed in the rubber matrix. The rubber matrix provides flexibility and elasticity, and the modified ceramic microspheres can play a role in dispersing stress, and synergistically achieve the effect of toughening. Moreover, the spherical structure of the ceramic microspheres can form a more tortuous path in the rubber matrix, further hindering the penetration of gas and small molecular substances, and improving the corrosion resistance of the butyl rubber sealing material.

[0021] When the amount of modified ceramic microspheres is too small, the modified ceramic microspheres cannot form an effective functional network, and a small amount of modified ceramic microspheres cannot effectively bear the composite, and the effect of enhancing the mechanical properties of the butyl rubber sealing material is not ideal.

[0022] When the amount of modified ceramic microspheres is too much, the excess rigid microspheres will form stress concentration points, damage the continuous phase structure of the rubber, and hinder the free movement and stretching of the rubber molecular chain, so that the resilience of the butyl rubber sealing material decreases and the compression permanent deformation increases.

[0023] Preferably, the preparation method of the modified ceramic microspheres comprises the following steps: Step 1: Place the ceramic microspheres in deionized water, ultrasonic cleaning for 20-30 min, separate by suction filtration, then wash and dry to obtain clean ceramic microspheres; Step 2: Soak the clean ceramic microspheres in dilute hydrochloric acid, stir at 60°C for 1h, wash with deionized water until the washing liquid is neutral, and then dry again to obtain active ceramic microspheres; Step 3: Add 3-mercaptopropyl triethoxysilane to deionized water, mix, then add to anhydrous ethanol to prepare a 5% 3-mercaptopropyl triethoxysilane solution, wherein the volume ratio of deionized water to anhydrous ethanol is 1:5, stir for 2h, then add the active ceramic microspheres, soak for 4h, separate by suction filtration, wash and dry to obtain the modified ceramic microspheres.

[0024] By adopting the technical scheme, firstly, the surface of the ceramic microspheres is cleaned, and the clean ceramic microspheres are soaked in dilute hydrochloric acid, so that the ceramic microspheres can be deeply cleaned, and the number of hydroxyl groups on the surface of the ceramic microspheres is increased, and the activity of the hydroxyl groups is enhanced, and then the ceramic microspheres are modified by 3-mercaptopropyl triethoxysilane, the ethoxyl group in the 3-mercaptopropyl triethoxysilane molecule is hydrolyzed to form silanol, which can react with the hydroxyl groups on the surface of the ceramic microspheres to form a firm Si-O-Si covalent bond, thereby improving the compatibility of the ceramic microspheres and the rubber matrix, and the 3-mercaptopropyl triethoxysilane also has a mercapto group, which can react with bromine atoms in brominated isobutylene-p-methylstyrene copolymer during vulcanization to form a firm C-S bond, so that the ceramic microspheres can be chemically crosslinked together with the rubber network through the "molecular bridge", so that the stress can be effectively transmitted from the relatively soft rubber matrix to the high-rigidity ceramic microspheres, thereby enabling the butyl rubber sealing material to not only maintain the elasticity of rubber but also obtain higher strength, tear resistance and durability.

[0025] Preferably, the ceramic microspheres are zirconia ceramic microspheres.

[0026] By adopting the technical scheme, the zirconia ceramic has high hardness and high toughness at the same time, and when the zirconia ceramic microspheres are dispersed in the rubber matrix, the high hardness thereof can act as a "rigid support point" to avoid the rupture of rubber molecular chains due to stress concentration during the compression and flexing of the dispersed rubber, thereby significantly improving the tear strength and flexing fatigue resistance of the butyl rubber sealing material, and the high toughness thereof can meet the demand of the elastic deformation of the rubber, and the zirconia ceramic microspheres are not easy to break during the repeated compression and rebound of the butyl rubber sealing material, and can maintain the function of "stress dispersion" for a long time, thereby ensuring the stability of the elasticity and compression permanent deformation of the butyl rubber sealing material.

[0027] In addition, the zirconia ceramic microspheres also have excellent high-temperature resistance and heat insulation, the high-temperature resistance thereof can effectively inhibit the thermal oxidative aging rate of the rubber molecular chains at high temperature, and can also avoid the destruction of the rubber crosslinking network caused by the failure of the ceramic microspheres at high temperature, and the heat insulation of the zirconia ceramic microspheres can form a "multilayer air-zirconia" composite heat insulation barrier in the rubber, so as to realize the synergistic effect of the low thermal conductivity of air and the low heat conduction of zirconia, effectively block the transmission of external heat to the temple part of the rubber, reduce the damage of thermal oxygen to the rubber molecular chains, and further improve the heat aging resistance of the butyl rubber sealing material.

[0028] At the same time, the surface of the zirconia has no easily reactive groups, and has good chemical corrosion resistance, so that the zirconia ceramic microspheres are prevented from "leaching out" or "degrading" due to reaction with the medium, thereby ensuring the continuity and sealing performance of the rubber matrix.

[0029] Preferably, the plasticizer is epoxy soybean oil.

[0030] By adopting the technical scheme, the epoxy soybean oil molecule contains long-chain fatty acid ester structure and epoxy group at the same time, the long-chain fatty acid ester group can be combined with the non-polar main chain of butyl rubber through van der Waals force, the epoxy group can occur nucleophilic ring-opening reaction with C-Br bond in brominated isobutylene-p-methylstyrene copolymer, the compatibility of brominated isobutylene-p-methylstyrene copolymer and butyl rubber is realized, the butyl rubber sealing material can be uniformly dispersed in the rubber matrix, the uniformity of the rubber system is maintained for a long time, and the mechanical properties and sealing stability of the butyl rubber sealing material are ensured. In the mixing stage, the epoxy soybean oil can penetrate between the rubber molecular chains, weaken the intermolecular force, reduce the Mooney viscosity of the rubber compound, make the fillers such as carbon black and modified ceramic microspheres more easily dispersed, reduce the mixing time, and avoid the extrusion and molding defects caused by the over-hardness of the rubber compound. After vulcanization, the long-chain structure can “flexibly connect” the rubber molecular chains, improve the elasticity and elongation of the rubber, and improve the flex fatigue resistance and compression permanent deformation of the butyl rubber sealing material.

[0031] The epoxy group of the epoxy soybean oil also has a free radical trapping ability, and can react with free radicals generated by thermal oxidative aging of the rubber molecular chain at high temperature, interrupt the auto-oxidation chain reaction, and replicate the antioxidant RD to inhibit thermal oxidative aging. Moreover, the epoxy group of the epoxy soybean oil can react with the hydroxymethyl group of the alkyl phenolic resin during the heating and vulcanization process, indirectly adjust the crosslinking activity of the alkyl phenolic resin, avoid “local over-crosslinking” caused by uneven distribution of bromine atoms in the brominated isobutylene-p-methylstyrene copolymer, and in the vulcanization process, the C-Br bond of the brominated isobutylene-p-methylstyrene copolymer can be broken to generate hydrogen bromide, the epoxy group of the epoxy soybean oil can trap the hydrogen bromide, and the epoxy group of the epoxy soybean oil can also react with trace free bromine in the brominated butyl rubber, reduce the catalytic degradation effect of bromine atoms on the rubber molecular chain, and indirectly protect the stability of the rubber crosslinking network.

[0032] In a second aspect, the application provides a preparation method of a butyl rubber sealing material, which adopts the following technical scheme: A preparation method of a butyl rubber sealing material, comprising the following steps: S1, mixing butyl rubber, brominated isobutylene-p-methylstyrene copolymer, carbon black, stearic acid, antioxidant and plasticizer according to the formula amount, then carrying out one-stage mixing, then adding zinc oxide and alkyl phenolic resin to carry out two-stage mixing, to obtain a mixed rubber; S2, cooling and thinning the mixed rubber, and then punching 3-6 triangular bags to obtain a butyl rubber sealing material.

[0033] By adopting the technical scheme, the butyl rubber sealing material is prepared through one-stage mixing, two-stage mixing, cooling and shaping, which is simple in process and easy to operate, and a butyl rubber sealing material with excellent performance is prepared.

[0034] Preferably, in S1, the modified ceramic microspheres are mixed with the formula amount of butyl rubber, brominated isobutylene-p-methylstyrene copolymer, carbon black, stearic acid, antioxidant and plasticizer for one-stage mixing, then zinc oxide and alkyl phenolic resin are added for two-stage mixing to obtain a mixed rubber.

[0035] By adopting the above technical scheme, the modified ceramic microspheres are added in S1, which helps to effectively shear and disperse the modified ceramic microspheres into the rubber compound and prevent agglomeration.

[0036] To sum up, the present application includes at least one of the following beneficial technical effects: 1. The present application compounding butyl rubber and brominated isobutylene-p-methylstyrene copolymer, butyl rubber provides ideal airtightness and heat aging resistance, the addition of brominated isobutylene-p-methylstyrene copolymer can introduce bromine atoms, which can realize co-vulcanization with butyl rubber, improve the vulcanization speed of the mixed rubber, and ensure that a uniform and stable co-crosslinking network can be formed between the molecules of the two rubbers. The addition of alkyl phenolic resin vulcanizing agent can form high-energy C-C bonds between the molecules of the two rubbers, effectively improve the heat aging resistance of butyl rubber sealing material, reduce the compression set, and thus obtain butyl rubber sealing material with excellent performance; 2. The present application compounding antioxidant RD and antioxidant 4020 into an antioxidant, the polymer structure of antioxidant RD can "anchor" the molecules of antioxidant 4020, reduce the volatilization or extraction of antioxidant 4020 at high temperature, effectively prolong the action time of antioxidant 4020, and the quinone imine derivative generated after antioxidant 4020 terminates free radicals can react with the amine intermediates generated by the decomposition of antioxidant RD to form more stable protective molecules, further strengthening the free radical capture efficiency; 3. The present application adds modified ceramic microspheres, which can play the role of "ball bearing" in the rubber compound, effectively reduce the viscosity of the polymer melt, improve the mixing and extrusion process, and reduce processing defects. Moreover, the modified ceramic microspheres have certain compressibility, which can adjust the hardness and compression set performance of the rubber compound to adapt to different sealing application scenarios. DETAILED DESCRIPTION

[0037] The raw materials in the present application include the following parts: Butyl rubber: using a commercially available product of Exxon™ Butyl 268S Rubber from Exxon Mobil Corporation; Brominated isobutylene-p-methylstyrene copolymer: using a commercially available product of Exxpro™ 3035 Specialty Elastomer from Exxon Mobil Corporation; Alkylphenol formaldehyde resin vulcanizing agent: The alkylphenol formaldehyde resin vulcanizing agent in the present application is taken as an example, and the alkylphenol formaldehyde resin vulcanizing agent with a CAS number of 25085-50-1 is used. Antioxidant RD: A commercially available product with a CAS number of 26780-96-1 is used. Antioxidant 4020: A commercially available product with a CAS number of 793-24-8 is used. Microcrystalline wax: A commercially available product with a CAS number of 8001-75-0 is used. Epoxy soybean oil: A commercially available product with a CAS number of 8013-07-8 is used. Ceramic microspheres: Ceramic microspheres with a particle size of 0.1 mm from Yixing Snail Ceramics Technology Co., Ltd. are used. Mercaptopropyl triethoxysilane: A commercially available product with a CAS number of 14814-09-6 is used.

[0038] The present application is further described in detail below in combination with examples and comparative examples. Example 1

[0039] A preparation method of a butyl rubber sealing material, comprising the following steps: S1, 6 kg of butyl rubber and 4 kg of brominated isobutylene-p-methylstyrene copolymer are put into a mixer, and the pressure is increased to 0.7 MPa, and mixed for 4 min, and the mixing temperature is 30 ℃, then 4 kg of carbon black, 0.2 kg of stearic acid, 0.2 kg of antioxidant and 0.8 kg of plasticizer are mixed and then subjected to a first-stage mixing, and the mixing time is 8 min, and the mixing temperature is 60 ℃, then 0.4 kg of zinc oxide and 1 kg of alkylphenol formaldehyde resin vulcanizing agent are added and subjected to a second-stage mixing, and the mixing time is 3 min, and the mixing temperature is 90 ℃, and after the mixing is completed, the rubber is discharged to obtain a mixed rubber; S2, the mixed rubber is cooled, thin-passed, and then packed into three triangular bags, and then sheeted out, and then placed for 10 h to obtain the butyl rubber sealing material.

[0040] The antioxidant is a mixture of antioxidant RD and antioxidant 4020, and the mixing mass ratio of antioxidant RD to antioxidant 4020 is 2:1, and the plasticizer is epoxy soybean oil.

[0041] Examples 2-3 Examples 2-3 are prepared on the basis of the preparation method of Example 1, and the components of the butyl rubber sealing material are adjusted, and the specific adjustments are shown in Table 1.

[0042] Comparative examples 1-2 Comparative examples 1-2 are prepared on the basis of the preparation method of Example 1, and the components of the butyl rubber sealing material are adjusted, and the specific adjustments are shown in Table 1.

[0043] Performance detection test The butyl rubber sealing materials of the above-mentioned Examples 1-3 and Comparative Examples 1-2 were analyzed, and the specific detection methods were as follows: 1. Heat aging resistance The tensile strength and elongation at break of the butyl rubber sealing material were detected according to the standard detection method specified in ISO 37, and then the tensile strength and elongation at break of the butyl rubber sealing material were tested after being placed at 150°C for 70h, and compared with the tensile strength and elongation at break before aging of the butyl rubber sealing material, to obtain the tensile strength change rate and elongation at break change rate, thereby indicating the aging resistance of the butyl rubber sealing material.

[0044] 2. Compression set The compression set performance of the butyl rubber sealing material was detected according to the standard detection method specified in ISO 815.

[0045] 3. Air tightness The oxygen permeation coefficient of the butyl rubber sealing material was tested according to the standard detection method specified in ISO 15105-1:2007 According to the above detection methods, the test results of Examples 1-3 and Comparative Examples 1-2 were obtained, as shown in Table 1 below.

[0046] Table 1 Composition and performance test table of butyl rubber sealing material of Examples 1-3 and Comparative Examples 1-2

[0047] Referring to Table 1, it can be seen from Comparative Examples 1-3 and Comparative Examples 1-2 that the performance of the butyl rubber sealing material of Example 1-3 is significantly better than that of Comparative Example 1-2, which may be because the butyl rubber is compounded with brominated isobutylene-p-methylstyrene copolymer, the butyl rubber has very low gas permeability and basic aging resistance, and the addition of brominated isobutylene-p-methylstyrene copolymer helps to improve the vulcanization efficiency and uniformity of the crosslinking network, thereby improving the aging resistance of the butyl rubber sealing material and reducing the compression set, so as to prepare butyl rubber sealing material with excellent performance.

[0048] Examples 4-6 Examples 4-6 were prepared on the basis of the preparation method of Example 1, and the components of the antioxidant were adjusted, as shown in Table 2.

[0049] Performance test The butyl rubber sealing materials of the above-mentioned Examples 1 and Examples 4-6 were analyzed, and the specific detection methods were as follows: 1. Ozone resistance The ozone resistance of the butyl rubber sealing material is detected according to the standard detection method specified in ISO 1431-1, and the butyl rubber sealing material is exposed for 200 hours under the condition that the ozone concentration is 50 PPhm, the elongation rate is 20%, and the temperature is 40 DEG C. The ozone resistance of the butyl rubber sealing material is reflected by the cracking degree of the surface of the butyl rubber sealing material, wherein, 0 level is no visible crack, 1 level is slight crack (length ≤1 mm, number ≤3), 2 level is moderate crack (length ≤2 mm, number ≤10), 3 level is significant crack (length ≤5 mm, or dense network crack), 4 level is severe crack (length >5 mm, or through crack), and 5 level is complete rupture.

[0050] According to the above detection method, the test results of example 1 and examples 4-6 are obtained, as shown in the following table 2.

[0051] Table 2: antioxidant components and performance test table of example 1 and examples 4-6

[0052] As shown in table 2, comparing example 1 and examples 4-6, the performance of the butyl rubber sealing material of example 1 is significantly better than that of examples 4-6, which may be because the antioxidant RD and antioxidant 4020 are compounded into an antioxidant, the polymer structure of antioxidant RD can "anchor" the molecules of antioxidant 4020, reduce the volatilization or extraction of antioxidant 4020 at high temperature, effectively prolong the action time of antioxidant 4020, and the quinone imine derivative generated after the termination of antioxidant 4020 can react with the amine intermediate generated by the decomposition of antioxidant RD to generate more stable protective molecules, further strengthening the efficiency of free radical capture.

[0053] Examples 7-10 Examples 7-10 are based on the preparation method of example 1, and the mixing mass ratio of antioxidant RD and antioxidant 4020 is adjusted, as shown in table 3.

[0054] Performance test The butyl rubber sealing materials of example 1 and examples 7-10 are analyzed, and the specific detection method is as follows: 1. Flex fatigue resistance The flex fatigue resistance of the butyl rubber sealing material is tested according to the standard detection method specified in JIS-K 6260.

[0055] According to the above detection method, the test results of example 1 and examples 7-10 are obtained, as shown in the following table 3.

[0056] Table 3. Mixing mass ratio of antioxidant RD and antioxidant 4020 and performance test table of example 1 and examples 7-10

[0057] As shown in Table 3, it can be seen from comparative example 1 and examples 7-10 that when the mixing mass ratio of antioxidant RD and antioxidant 4020 is 1-3:1, and when the mixing mass ratio of antioxidant RD and antioxidant 4020 is 2:1, the performance of the obtained butyl rubber sealing material is optimal, which may be because when the proportion of antioxidant RD is too high, the insufficient addition amount of antioxidant 4020 leads to insufficient thickness and poor compactness of the surface "amine protective film", and ozone easily penetrates the film layer to attack the rubber double bond, resulting in molecular chain rupture, lack of chemical capture of antioxidant 4020, direct destruction of the rubber structure, further aggravation of aging cracking, and decrease in the flex fatigue resistance of the butyl rubber sealing material; when the proportion of antioxidant RD is too low, it cannot effectively interrupt the free radical chain reaction and decompose hydroperoxide, resulting in uncontrolled thermal oxidative aging, which leads to decrease in the elasticity of the butyl rubber sealing material, and the destruction of the crosslinked network leads to increase in the compression set of the butyl rubber sealing material, resulting in failure of the sealing performance.

[0058] Example 11 Example 11 is prepared based on the preparation method of example 1, in S1, 1 kg of modified ceramic microspheres is mixed with butyl rubber, brominated isobutylene-p-methylstyrene copolymer, carbon black, stearic acid, antioxidant and plasticizer for one-stage mixing, and zinc oxide and alkyl phenol formaldehyde resin are added for two-stage mixing to obtain a mixed rubber.

[0059] Preparation of the modified ceramic microspheres includes the following steps: Step 1: The zirconia ceramic microspheres are placed in deionized water and ultrasonically cleaned for 30 min, separated by suction filtration, washed with anhydrous ethanol for 2 times, and then transferred into a vacuum drying oven and dried at 80°C for 4 h to obtain clean ceramic microspheres; Step 2: The clean ceramic microspheres are soaked in 0.1 mol / L dilute hydrochloric acid, stirred at 60°C for 1 h, washed with deionized water until the washing liquid is neutral, and then transferred into a vacuum drying oven and dried at 80°C to obtain active ceramic microspheres; Step 3: 3-mercaptopropyl triethoxysilane was added into deionized water and mixed, then added into anhydrous ethanol to prepare a 5% 3-mercaptopropyl triethoxysilane solution by mass fraction, wherein the volume ratio of deionized water to anhydrous ethanol was 1:5, and the mixture was stirred at 50°C for 2h, then the active ceramic microspheres were added, and the mixture was soaked at 60°C for 4h, then filtered and separated, washed with anhydrous ethanol for 3 times, and then transferred into a vacuum drying oven and dried at 80°C for 4h to obtain the modified ceramic microspheres, and the mixing mass ratio of zirconia ceramic microspheres to 3-mercaptopropyl triethoxysilane was 40:1.

[0060] Examples 12-15 Examples 12-15 were prepared based on the preparation method of Example 11, and the amount of modified ceramic microspheres added was adjusted, as shown in Table 4.

[0061] Performance detection test The butyl rubber sealing materials of Examples 1 and 11-15 were analyzed, and the specific detection methods were as follows: 1. Hardness The hardness of the butyl rubber sealing material was detected according to the standard detection method specified in ISO 868.

[0062] 2. Corrosion resistance The butyl rubber sealing material was placed in 10% dilute hydrochloric acid and 10% dilute sodium hydroxide solution respectively, soaked for 24h, and then the tensile strength test was performed.

[0063] According to the above detection method, the test results of Examples 1 and 11-15 were obtained, as shown in Table 4.

[0064] Table 4: Modified ceramic microspheres addition amount and performance detection table of Examples 1 and 11-15

[0065] As shown in Table 4, the performance of the butyl rubber sealing material of Examples 11-15 was significantly better than that of Example 1, which may be because the modified ceramic microspheres not only reduced the viscosity of the polymer melt and reduced the processing defects of the butyl rubber sealing material, but also adjusted the hardness and compression permanent deformation performance of the material.

[0066] In addition, the modified ceramic microspheres can be uniformly dispersed in the rubber matrix, the rubber matrix can provide flexibility and elasticity, the modified ceramic microspheres can play a role in dispersing stress, and the modified ceramic microspheres can also form more tortuous paths in the rubber matrix to prevent the penetration of gas and small molecules, thereby improving the corrosion resistance of the butyl rubber sealing material.

[0067] As can be seen from Comparative Examples 11-15, when the amount of the modified ceramic microspheres is too small, the modified ceramic microspheres cannot form an effective functional network, and the small amount of the modified ceramic microspheres cannot effectively bear the load, and the effect of enhancing the mechanical properties of the butyl rubber sealing material is not ideal; when the amount of the modified ceramic microspheres is too large, the excess rigid microspheres will form stress concentration points, destroy the continuous phase structure of the rubber, and hinder the free movement and stretching of the rubber molecular chain, so that the resilience of the butyl rubber sealing material decreases and the compression permanent set increases.

[0068] Example 16 Example 16 is based on the preparation method of Example 11, and 1 kg of zirconia ceramic microspheres is replaced with 1 kg of silica ceramic microspheres.

[0069] The butyl rubber sealing material of Example 16 is subjected to the above performance detection, and the detection results are shown in Table 5.

[0070] Table 5 Performance detection table of Example 11 and Example 16

[0071] As can be seen from Table 5, Comparative Example 11 and Example 16, the performance of the butyl rubber sealing material added with zirconia ceramic microspheres is significantly better than that of the butyl rubber sealing material added with silica ceramic microspheres, which may be because the zirconia ceramic microspheres have a unique "phase change toughening" property, when they are filled into the butyl rubber matrix, the zirconia not only can enhance the mechanical properties of the material through "rigid support", but also can avoid its own brittle fracture due to high toughness, and the zirconia has stronger chemical inertness, which is suitable for the complex application environment of the butyl rubber sealing material.

[0072] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A butyl rubber sealing material, characterized in that, It includes the following components in parts by weight: 50-70 parts butyl rubber, 30-50 parts brominated isobutylene-p-methylstyrene copolymer, 30-50 parts carbon black, 8-12 parts alkylphenol resin vulcanizing agent, 3-5 parts zinc oxide, 1-3 parts stearic acid, 1-3 parts antioxidant, and 5-10 parts plasticizer.

2. The butyl rubber sealing material according to claim 1, characterized in that, The antioxidant is at least one of antioxidant RD, antioxidant 4020, and microcrystalline wax.

3. The butyl rubber sealing material according to claim 2, characterized in that, The antioxidant is a mixture of RD and antioxidant 4020.

4. The butyl rubber sealing material according to claim 3, characterized in that, The mixing mass ratio of antioxidant RD to antioxidant 4020 is 1-3:

1.

5. The butyl rubber sealing material according to claim 1, characterized in that, Modified ceramic microspheres are also added, with an addition amount of 5-15 parts.

6. The butyl rubber sealing material according to claim 5, characterized in that, The preparation method of the modified ceramic microspheres includes the following steps: Step 1: Place the ceramic microspheres in deionized water, ultrasonically clean for 20-30 minutes, filter and separate, then wash and dry to obtain clean ceramic microspheres; Step 2: Immerse the clean ceramic microspheres in dilute hydrochloric acid and stir at 60°C for 1 hour. Wash with deionized water until the washing solution is neutral and then dry again to obtain active ceramic microspheres. Step 3: Add 3-mercaptopropyltriethoxysilane to deionized water and mix, then add it to anhydrous ethanol to prepare a 5% (w / w) 3-mercaptopropyltriethoxysilane solution. The volume ratio of deionized water to anhydrous ethanol is 1:

5. After stirring for 2 hours, add the active ceramic microspheres, soak for 4 hours, filter and separate, wash and dry to obtain the modified ceramic microspheres.

7. The butyl rubber sealing material according to claim 6, characterized in that, The ceramic microspheres are zirconia ceramic microspheres.

8. The butyl rubber sealing material according to claim 1, characterized in that, The plasticizer is epoxidized soybean oil.

9. A method for preparing a butyl rubber sealing material according to claims 1-8, characterized in that, Includes the following steps: S1. Butyl rubber, brominated isobutylene-p-methylstyrene copolymer, carbon black, stearic acid, antioxidant and plasticizer are mixed according to the formula and then mixed in a first stage. Zinc oxide and alkylphenol resin are then added and mixed in a second stage to obtain the compound. S2. Cool the compounded rubber, pass it through a thin sheet, form 3-6 triangular packages, and then sheet it out. After standing, you will get butyl rubber sealing material.

10. The method for preparing a butyl rubber sealing material according to claim 9, characterized in that, In S1, the modified ceramic microspheres of the specified amount are mixed with butyl rubber, brominated isobutylene-p-methylstyrene copolymer, carbon black, stearic acid, antioxidant and plasticizer for a first-stage mixing, and then zinc oxide and alkylphenol resin are added for a second-stage mixing to obtain the compound.

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